How use multi-threading with this - php

Question

I've been reading up on multi-threading with PHP, but I'm having a tough time integrating it into my command line php script.
I read multithreading
and multithread foreach.
But I'm really not sure. Any thoughts how to apply multi-threading here? The reason I need multi-threading here is that Telnet takes forever (see shell script). But I can't write to my DB concurrently ($stmt2). I'm looping through my list of devices with $stmt->fetch.
Maybe I should do something like run task specifically, with just the telnet/shell script call in the task, like that example:
$task = new class extends Thread {
private $response;
public function run()
{
$content = file_get_contents("http://google.com");
preg_match("~<title>(.+)</title>~", $content, $matches);
$this->response = $matches[1];
}
};
$task->start() && $task->join();
var_dump($task->response); // string(6) "Google"
But, I'm getting the error when I try to add this to my code below:
PHP Parse error: syntax error, unexpected T_CLASS in /opt/IBM/custom/NAC_Dslam/calix_swVerThreaded.php on line 100
this is the line:
$task = new class ...
My script looks like this:
$stmt =$mysqli->prepare("SELECT ip, model FROM TableD WHERE vendor = 'Calix' AND model in ('C7','E7') AND sw_ver IS NULL LIMIT 6000"); //AND ping_reply IS NULL AND software_version IS NULL
$stmt->bind_result($ip, $model); //list of ip's
if(!$stmt->execute())
{
//err
}
$stmt2 = $mysqli2->prepare("UPDATE TableD SET sw_ver = ?
WHERE vendor = 'Calix'
AND ip = ? ");
$stmt2->bind_param("ss", $software, $ip);
while($stmt->fetch()) {
//initializing var's
if(pingAddress($ip)=="alive") { //Ones that don't ping are dead to us.
///////this is the part that takes forever and should be multi-threaded/////
//Call shell script to telnet to calix dslam and get version for that ip
if($model == "C7"){
$task = new class extends Thread {
private $itsOutput;
public function run()
{
exec ("./calix_C7_swVer.sh $ip", $itsOutput);//takes forever/telnet
//in shell script. Can't
//be fixed. Each time I
//call this script it's a
//different ip
}
};
$task->start() && $task->join();
var_dump($task->itsOutput); //should be returned output above //takes forever to telnet
//$output = $task->itsOutput;
$output2=array_reverse($output,true);
if (!(preg_grep("/DENY/", $output2))){
$found = preg_grep("/COMPLD/", $output2);
$ind = key($found);
$version = explode(",", $output[$ind+1]);
if(strlen($version[3])>=1) { //if sw ver came back in an acceptable size
$software = $version[3];
$software = trim($software,'"'); //trim double quote (usually is there)
print "sw ver after trim: " . $software . "\n";
if(!$stmt2->execute()) { //write sw version to netcool db
$tempErr = "Failed to insert into dslam_elements_nac: " . $stmt2->error;
printf($tempErr . "\n"); //show mysql execute error if exists
$err->logThis($tempErr);
}
if(!$stmtX->execute()) { //commit it
$tempErr = "Failed to commit dslam_elements_nac: " . $stmtX->error;
printf($tempErr . "\n"); //show mysql execute error if exists
$err->logThis($tempErr);
}
} //we got a version back
else { //version not retrieved
//error processing
} //didn't get sw ver
} //not deny
} //c7
else if($model == "E7") {
exec ("./calix_E7_swVer.sh $ip", $output);
$output2=array_reverse($output,true);
if (!(preg_grep("/DENY/", $output2))){
$found = preg_grep("/yes/", $output2);
$ind = key($found);
$version = explode(" ", $output[$ind]);
if(strlen($version[5])>=1) { //if sw ver came back in an acceptable size
$software = $version[5];
print "sw ver after trim: " . $software . "\n";
if(!$stmt2->execute()) { //write sw version to netcool db
$tempErr = "Failed to insert into dslam_elements_nac: " . $stmt2->error;
printf($tempErr . "\n"); //show mysql execute error if exists
$err->logThis($tempErr);
}
if(!$stmtX->execute()) { //commit it
//err processing
}
} //we got a version back
else { //version not retrieved
//handle it
} //didn't get sw ver
} //not deny
}
} //while
update
I'm trying this (pcntl_fork), but it doesn't seem to be quite what I need because when I sleep(30), which I think is similar to my shell script call, other processes don't continue and do the next one.
<?php
declare(ticks = 1);
$max=10;
$child=0;
$res = array("aabc", "bcd", "cde", "eft", "ggg", "hhh", "iii", "jjj", "kkk", "lll", "mmm", "nnn", "ooo", "ppp", "qqq", "aabc", "bcd", "cde", "eft", "ggg", "hhh", "iii", "jjj", "kkk", "lll", "mmm", "nnn", "ooo", "ppp", "qqq");
function sig_handler($signo) {
global $child;
switch ($signo) {
case SIGCHLD:
//echo "SIGCHLD receivedn";
// clean up zombies
$pid = pcntl_waitpid(-1, $status, WNOHANG);
$child -= 1;
//exit;
}
}
pcntl_signal(SIGCHLD, "sig_handler");
//$website_scraper = new scraper();
foreach($res as $r){
while ($child >= $max) {
sleep(5); //echo " - sleep $child n";
//pcntl_waitpid(0,$status);
}
$child++;
$pid=pcntl_fork();
if ($pid==-1) {
die("Could not fork:n");
}
elseif ($pid) {
// we're in the parent fork, dont do anything
}
else {
//example of what a child process could do:
print "child process stuff \n";
sleep(30);
//$website_scraper -> scraper("http://foo.com");
exit;
}
while(pcntl_waitpid(0, $status) != -1) { //////???
$status = pcntl_wexitstatus($status);
echo "child $status completed \n";
}
print "did stuff \n";
}
?>

Answer 1

I've been reading up on multi-threading with PHP
Don't. PHP threading has very limited utility, as it cannot be used in a web server environment. It can only be used in command-line scripts.
The author of the PHP pthreads extension has written:
pthreads v3 is restricted to operating in CLI only: I have spent many years trying to explain that threads in a web server just don't make sense, after 1,111 commits to pthreads I have realised that, my advice is going unheeded.
So I'm promoting the advice to hard and fast fact: you can't use pthreads safely and sensibly anywhere but CLI.
If you need to communicate with multiple network devices in parallel, consider using stream_select to perform asynchronous I/O, or running multiple PHP processes as part of a worker queue to manage the connections.